From: Duy Nguyen <pclouds@gmail.com>
Date: Sat, 12 May 2018 12:13:06 GMT
Subject: Re: [PATCH 01/12] blame: use commit-slab for blame suspects instead of commit->util
Message-ID: <CACsJy8BaeiH1xcB94sPX511Gc+FrWW==XRuModE3Csz9J_i2Kw@mail.gmail.com>
In-Reply-To: <20180512092241.GD28279@sigill.intra.peff.net>

On Sat, May 12, 2018 at 11:22 AM, Jeff King <peff@peff.net> wrote:
> On Sat, May 12, 2018 at 10:00:17AM +0200, Nguyễn Thái Ngọc Duy wrote:
>
>> +define_commit_slab(blame_suspects, struct blame_origin *);
>> +static struct blame_suspects blame_suspects;
>> +
>> +struct blame_origin *get_blame_suspects(struct commit *commit)
>> +{
>> +     struct blame_origin **result;
>> +
>> +     result = blame_suspects_peek(&blame_suspects, commit);
>> +
>> +     return result ? *result : NULL;
>> +}
>
> Hmm. You need this helper because you want to be able to peek and get a
> NULL. But that's already what _at() would return, with the only
> difference that we may extend the slab just to return NULL.
>
> I wonder how much it matters in practice. We'd generally be extending
> the slab to hit every commit anyway in this case, I would think.

I don't know much about blame so I stay very conservative ;-) If it's
safe to just do _at() here, I'll update this patch.

> I suppose it doesn't actually simplify the code that much to do it that
> way, though. We could get rid of this helper, but the caller would still
> look like:
>
>   for (p = *blame_suspects_at(o->commit); p; p = p->next)
>
> which is actually slightly uglier than get_blame_suspects(), because we
> have to do the pointer-dereference ourselves.

And the caller would need to include commit-slab.h too. I added
get_blame_suspects() because I wanted to avoid that.
-- 
Duy